1. Technical Field
The present invention relates to a vehicle seat belt retractor for use in a vehicle occupant restraint system, and is particularly directed to a seat belt retractor with a cinch mechanism which blocks rotation of a seat belt storage spool in a seat belt withdrawal direction in response to withdrawal of a predetermined amount of seat belt from the spool.
2. Background Art
A typical seat belt retractor includes a rotatable spool with seat belt webbing wound around the spool. The spool has a longitudinal central axis and is rotatable in a seat belt unwinding direction about its longitudinal central axis to enable the belt webbing to be extended about a vehicle occupant.
A typical cinch mechanism includes an actuatable locking mechanism which, when actuated, locks the spool from rotation in the belt unwinding direction. The locking mechanism actuates to lock the spool when the belt webbing has been unwound at least a predetermined amount from the spool. When the spool is locked from rotation in the belt unwinding direction, the belt webbing is cinched and thus unable to move in the belt unwinding direction.
When the belt webbing is cinched, the belt webbing can move only in the belt winding direction onto the spool. Typically, the belt webbing is unable to move in the belt unwinding direction until the belt webbing is returned to a fully wound condition on the spool. When the belt webbing is returned to the fully wound condition on the spool, the locking mechanism is actuated to release the spool for rotation in the belt unwinding direction.